Latest revision as of 14:13, 21 February 2025

Tunicate[edit]

Tunicates, also known as urochordates, are a group of marine animals that are part of the subphylum Tunicata. They are notable for their sac-like body structure and are found in oceans worldwide. Tunicates are an important part of the marine ecosystem and are closely related to vertebrates.

Anatomy and Physiology[edit]

Tunicates have a simple body plan that includes a tough outer "tunic" made of a cellulose-like carbohydrate. This tunic protects the animal and gives the group its name. The body of a tunicate is divided into two main regions: the siphons and the pharynx.

The incurrent siphon draws water into the body, where it passes through the pharynx. The pharynx is lined with cilia and mucus, which trap food particles. The filtered water is then expelled through the excurrent siphon.

Life Cycle[edit]

Tunicates have a complex life cycle that includes both a free-swimming larval stage and a sessile adult stage. The larval stage resembles a tadpole and possesses a notochord, a dorsal nerve cord, and a post-anal tail, which are characteristic features of the chordates.

Upon settling, the larva undergoes metamorphosis into the adult form, losing its tail and notochord. The adult tunicate is typically sessile, attaching itself to a substrate.

Diversity[edit]

Tunicates are divided into three main classes: Ascidiacea, Thaliacea, and Appendicularia.

Ascidiacea[edit]

Ascidians, or sea squirts, are the most common type of tunicate. They are sessile as adults and can be solitary or colonial. Colonial ascidians, such as Botrylloides violaceus, form large, colorful colonies.

Thaliacea[edit]

Thaliaceans, including salps and pyrosomes, are free-floating and often form large colonies. Salps are barrel-shaped and move by contracting their bodies to pump water through their siphons.

Appendicularia[edit]

Appendicularians, such as Oikopleura dioica, retain their larval characteristics throughout their life. They are small, free-swimming, and build a "house" of mucus to filter food from the water.

Ecological Role[edit]

Tunicates play a crucial role in marine ecosystems as filter feeders. They help maintain water quality by removing plankton and other particles from the water column. Some tunicates, like pyrosomes, can form large bioluminescent colonies that are visible at night.

Evolutionary Significance[edit]

Tunicates are of great interest to evolutionary biologists because they are considered the closest living relatives of vertebrates. The study of tunicate development and genetics provides insights into the evolution of chordates.

Related Pages[edit]

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-{{Short description|Marine invertebrate animals of the subphylum Tunicata}}
+= Tunicate =
-{{Taxobox
-| name = Tunicate
-| image = Tunicate.jpg
-| image_caption = A tunicate attached to a rock
-| regnum = [[Animalia]]
-| phylum = [[Chordata]]
-| subphylum = '''Tunicata'''
-}}
-'''Tunicates''' are marine invertebrate animals that belong to the subphylum '''Tunicata''', also known as '''Urochordata'''. They are part of the phylum [[Chordata]], which also includes vertebrates. Tunicates are characterized by their sac-like body structure and a tough outer covering called a "tunic," which is made of a cellulose-like carbohydrate.
+[[File:Tunicate_komodo.jpg|thumb|right|A tunicate in its natural habitat]]
-==Anatomy and Physiology==
+Tunicates, also known as urochordates, are a group of marine animals that are part of the subphylum [[Tunicata]]. They are notable for their sac-like body structure and are found in oceans worldwide. Tunicates are an important part of the marine ecosystem and are closely related to vertebrates.
-Tunicates exhibit a wide range of body forms, but they generally have a simple body plan. The adult tunicate body is typically composed of a [[siphon]] system, a [[pharynx]] with gill slits, and a digestive tract. The tunic, which gives them their name, is secreted by the epidermis and provides protection.
-===Larval Stage===
+== Anatomy and Physiology ==
-Tunicates have a distinct larval stage that resembles a tadpole and possesses a notochord, a dorsal nerve cord, and a post-anal tail, which are characteristic features of chordates. This larval stage is free-swimming and is crucial for dispersal.
-===Adult Stage===
+[[File:Bluebell_tunicates_Nick_Hobgood.jpg|thumb|left|Bluebell tunicates]]
-In most tunicates, the adult stage is sessile, meaning they attach to a substrate such as rocks or the ocean floor. However, some tunicates, like those in the class [[Thaliacea]], remain pelagic and free-floating throughout their life.
-==Reproduction==
+Tunicates have a simple body plan that includes a tough outer "tunic" made of a cellulose-like carbohydrate. This tunic protects the animal and gives the group its name. The body of a tunicate is divided into two main regions: the [[siphon]]s and the [[pharynx]].
-Tunicates can reproduce both sexually and asexually. Sexual reproduction involves the release of sperm and eggs into the water column, where fertilization occurs. Asexual reproduction is common in colonial tunicates, where budding leads to the formation of new individuals.
-==Ecology==
+The incurrent siphon draws water into the body, where it passes through the pharynx. The pharynx is lined with cilia and mucus, which trap food particles. The filtered water is then expelled through the excurrent siphon.
-Tunicates are found in oceans worldwide, from shallow waters to the deep sea. They play a significant role in marine ecosystems as filter feeders, consuming plankton and organic particles suspended in the water. This feeding activity helps maintain water quality and clarity.
-==Classification==
+== Life Cycle ==
-Tunicates are divided into three main classes:
-* '''[[Ascidiacea]]''' - Commonly known as sea squirts, these are mostly sessile tunicates that attach to substrates.
+Tunicates have a complex life cycle that includes both a free-swimming larval stage and a sessile adult stage. The larval stage resembles a tadpole and possesses a notochord, a dorsal nerve cord, and a post-anal tail, which are characteristic features of the [[Chordata|chordates]].
-* '''[[Thaliacea]]''' - Includes free-floating tunicates such as salps, which form large colonies.
-* '''[[Appendicularia]]''' - Also known as larvaceans, these tunicates retain their larval characteristics throughout life.
-==Importance to Humans==
+Upon settling, the larva undergoes metamorphosis into the adult form, losing its tail and notochord. The adult tunicate is typically sessile, attaching itself to a substrate.
-Tunicates are of interest to scientists due to their evolutionary relationship to vertebrates. They are also studied for their potential in biotechnology and medicine, as some species produce bioactive compounds with pharmaceutical applications.
-==Gallery==
+== Diversity ==
-[[File:Tunicate_ascidian.jpg|thumb|left|A colonial ascidian tunicate]]
-[[File:Salp_chain.jpg|thumb|right|A chain of salps, a type of thaliacean tunicate]]
+[[File:Botrylloides_violaceus_(cropped).jpg|thumb|right|Botrylloides violaceus]]
+Tunicates are divided into three main classes: [[Ascidiacea]], [[Thaliacea]], and [[Appendicularia]].
+=== Ascidiacea ===
+Ascidians, or sea squirts, are the most common type of tunicate. They are sessile as adults and can be solitary or colonial. Colonial ascidians, such as Botrylloides violaceus, form large, colorful colonies.
+=== Thaliacea ===
+[[File:Salp_colony,_Aorangaia_PA171899.JPG|thumb|left|A colony of salps]]
+Thaliaceans, including [[salps]] and [[pyrosomes]], are free-floating and often form large colonies. Salps are barrel-shaped and move by contracting their bodies to pump water through their siphons.
+=== Appendicularia ===
+[[File:Oikopleura_dioica.gif|thumb|right|Oikopleura dioica]]
+Appendicularians, such as Oikopleura dioica, retain their larval characteristics throughout their life. They are small, free-swimming, and build a "house" of mucus to filter food from the water.
+== Ecological Role ==
+Tunicates play a crucial role in marine ecosystems as filter feeders. They help maintain water quality by removing plankton and other particles from the water column. Some tunicates, like pyrosomes, can form large bioluminescent colonies that are visible at night.
+== Evolutionary Significance ==
+[[File:Appendicularia_(YPM_IZ_096169).jpeg|thumb|left|Appendicularia specimen]]
+Tunicates are of great interest to evolutionary biologists because they are considered the closest living relatives of vertebrates. The study of tunicate development and genetics provides insights into the evolution of chordates.
+== Related Pages ==
-==Related pages==
 * [[Chordate]]
-* [[Invertebrate]]
+* [[Vertebrate]]
 * [[Marine biology]]
+* [[Filter feeder]]
-[[Category:Tunicata]]
+[[Category:Tunicates]]
-[[Category:Chordates]]
-[[Category:Marine animals]]

Tunicate: Difference between revisions